Loss of visibility caused by the reflection of sunlight or illumination or the like at the interfaces (surfaces) where various displays, lenses, show windows or vehicle components (such as covers for meters or monitors for vehicle navigation devices) or the like contact the air has been an ongoing problem. An example of a known method of reducing this reflection is a method in which multiple layers of films having different refractive indices are laminated, so that the reflected light at the film surface and the reflected light at the interface between the film and the substrate cancel each other out by interference. These films are usually produced by methods such as sputtering, vapor deposition or coating or the like. However, with these types of methods, even if the number of laminated films is increased, there is a limit to the reduction in the reflectance and the wavelength dependency of the reflectance. Further, in order to reduce the number of laminated films from the viewpoint of reducing production costs, materials of lower refractive index are required.
Introducing air into a material by some type of method is effective in lowering the refractive index of the material. One known example of this type of method is a method of forming a nano concave-convex structural body on the surface of the film. A film (anti-reflective film) in which a nano concave-convex structural body is formed on a substrate has a cross-section when cut through the direction of the film surface that varies continuously, with the refractive index gradually increasing from the air down to the substrate, and therefore functions as an effective anti-reflective device. Further, this anti-reflective film exhibits superior optical performance which cannot be reproduced by other methods.
Because anti-reflective films having a nano concave-convex structural body on the surface are used at the interface that contacts the air, they require mainly soiling resistance and scratch resistance. However, nano concave-convex structural bodies tend to exhibit inferior soiling resistance and scratch resistance compared with molded bodies such as hard coatings having a smooth surface formed from the same resin composition.
Examples of the soiling on anti-reflective films are numerous, including oily soiling, fingerprints, wax, dust or dirt, and the soiling resistance for anti-reflective films includes a property that inhibits the adhesion of these types of soiling, and a property that facilitates removal when soiling does adhere to the film.
Examples of known methods of imparting anti-reflective films with soiling resistance include methods in which a highly hydrophilic resin composition is used to hydrophilize the film, so that soiling which adheres to the film is lifted and wiped away by water (for example, see Patent Document 1).